Method of flocking textile fabric



April 13, 1954 s. M. SCHWARTZ ET AL 2,675,330 METHOD OF FLOCKING TEXTILE FABRIC Filed July 3, 1946 2 Sheets-Sheet 1 rfa.

Fig I 4 INVENTOR. Samuel Schwar-Tz l- Dame/ Gross April 13, 1954 s. M. SCHWARTZ ETAL 2,675,330

METHOD OF FLOCKING TEXTILE FABRIC Filed July 3, 1946 2 Sheets-Sheet 2 F19 F193 V W 7 f INVENTOR.

Samuel M 5chwarl'z1Dame/ G- Patented Apr. 13, t 1954 METHOD OF FLOCKING TEXTILE FABRIC Samuel M. Schwartz and Daniel Gross, Paterson,

N. J., assignors to Veiveray Corporation, Clifton, N. ,J., a corporation of New York Application July 3, 1946, Serial No. 681,402

1 Claim. 1

This invention relates generally to the production of piled surfaces and pile surfaced materials and more specifically to methods and apparatus directed. toward an eiiicient deposition of finely divided or fragmentary substances upon a material, previously coated with an adhesive, that moves through an electric field.

Among the objects of the invention is the provision of a unidirectional electric field from a conventional alternating current source.

Another novel object of the invention provides for the insertion of a glass plate in the electric field between two electrodes in order to avoid discharges between the two electrodes when larger currents inadvertently flow from the transformers and, furthermore, by varying the thickness of the glass dielectric, to regulate the voltage across the air gap in accordance with the requirements of different kinds of pile-deposition work.

Still another object of the invention is to provide a means for preventing or breaking a treeing of the fragmentary particles as they move adjacent to the surface of the material by me chanically interrupting the columns of massed particles through the medium of a moving, insulating belt.

Other objects include the utilization of means for the purpose of bringing the fragmentary particles or flock to the adhesive-coated material in a dry condition and at an optimum working temperature. Moreover, other advantageous features of the invention will be disclosed in the following more detailed description of the apparatus employed and of the manner in which it is applied. For this purpose, reference is directed to the accompanying schematic drawings in which:

Fig. 1 is a diagrammatic view of the essential apparatus shown largely in sectional elevation.

Fig. 2 is an enlarged plan view of the upper electrode.

Fig. 2a is an enlarged sectional elevation view of the upper electrode.

Fig. 3 is an enlarged plan view of another type of upper electrode.

Fig. 3a is an enlarged sectional elevation view oi. another type of upper electrode.

Referring to Fig. 1, numeral I indicates a hopper in which the pile 2 is stored preliminarily to sifting it through perforations G to fall upon the moving material or cloth 3. The hopper I may be rocked vigorously from side to side to facilitate a uniform distribution of the pile 2. The pile or flock 2 is fed to the hopper I in a passed slowly on a conveyor (not shown) through a chamber (not shown) heated to a temperature of 200 F. The space or the room in whichthe actual deposition of the pile is made is maintained at a constant temperature and at a low relative humidity by suitable refrigeration apparatus and silica gel. These precautions for maintaining the pile in a dry condition are necessary to insure an efficient electrification of all of the small particles.

If the hopper i is not rocked, the same effects can be obtained by vibrating periodically the screen 4 and the electrode or plate 5.

The bottom 6 of the hopper I is perforated to allow a steady stream of pile to fall upon the wire gauze t. As the pile 2 seeps through the meshes of the gauze 4, it falls upon the plate 5 which consists of a solid sheet of copper or brass containing many perforations 1 as shown in Fig. 2 or comprising many rods II of triangular cross section as illustrated in Fig. 3. Upon reaching the perforations or the interstices 'Lthe pile becomes subject to the action of the electric field between the electrode 5 and the electrode 8. In order to generate this electric field, commercial A. C. at volts is fed to two transformers 4a and resistances in series with the: electrodes 5 and 3. The voltage acrossthe plate electrodes 5 and 8 varies between 30,000 and 45,000 volts. The electrodes may be insulated from each other and the apparatus or one electrode may be grounded. In the air gap 9 between the electrodes is positioned a glass plate It approximately thick. The purpose of the glass plate is novel and important. If, during operation, a heavy discharge should develop between the plates at a given point a greater current would flow from the transformers, thus entailing a greater IR drop through the resistance and a decreased voltage across the air gap between the electrodes. The intervention of the glass plate [0 into the air gap 9 eliminates the possibility of such a discharge because its thickness is such as to prevent a breakdown under such voltage conditions-in marked contrast with the behavior of an unprotected air gap. Furthermore, since the dielectric constant of glass is smaller than that of air, by varying the thickness of the glass, the actual voltage across the free air gap cannot only be increased, but can be varied within desirable limits. For example, the voltage across the glass may be only 4000; thus leaving 26,000 volts across the free air gap. Hence, an increase in the thickness of the glass will result in an increase of the voltage per unit of distance across the free air gap. Depositions of difierent kinds of pile or flock on difierent kinds of material require varying voltages for optimum results and can be readily controlled by the features of the present invention.

It will be Observed in Fig. 2 that the perforations! have smooth and rounded edges in order to avoid developing an intensity of electrification at any sharp points or lines and, furthermore, that in Fig. 3 the rounded triangular rods H form slots or interstices that similarly prevent a clumping of the fragmentary particles of the pile on hair-line areas.

The flow of the flock in the electric field be tween the two electrodes is frequently impeded by the phenomenon of treeing or clumping. In the present invention, treeing is avoided by several methods. It has been discovered that .a periodic suspension of the electric field by switching off the current for one second during every four seconds is helpful in preventing the flock from concentrating on a plate. Agitation of the upper electrode also materially aids in minimizing the results of the treeing phenomenon. But, most effective of the several means employed, is the slow passage through the electric field, in close proximity to the glass plate ill, of a woolen belt [2. The woolen belt 12 minimizes the tendency toward treeing since it sweeps through the field through which the trees would form. Some of the flock may also pass through the interstices of the fabric 3 being flock-printed upon the Woolen belt. In Fig. 1, the belt i2, mounted on appropriate rollers I3, is moved slowly through the electric field in an opposite direction to that which the cloth or material is traversing. The belt t2, stretching transversely over the field, serves .as an insulated, mechanical sweeper to any potential trees or clumps of flock that may develop. Consequently, the pile falls in uniform. streams upon the adhesivecoated areas of the material 3 as it moves through the electric field, Brushes I4 remove excessive flock from the belt [2 as it moves over its rollers through the electric field. The material 3 is fed between the electrodes 5 and 8 by feed rollers. The unidirectional electrical field is obtained from a source of alternating current.

In the aforesaid description, details in respect to conventional equipment and methods have been omitted. For example, the material, upon the surface of which the pile is to be constructed, may be a fabric such as is ordinarily supplied in roll form. The adhesive may be applied to the fabric in various ways. The fabric may be fed to the electric field through various chains of interlocking rollers. However, such mechanisms are not an essential part of the novelty of the present invention. Likewise, the mechanisms conventionally employed for drying and re-rolling the piled materiaifdo not constitute an inventive phase of the embodiment described.

It is understood that the preferred equipment and method that have been described are only illustrative and are not to be construed as limitative upon the spirit and the scope of the present invention which is more specifically defined in the annexed claim.

We claim:

A low humidity method of fiock-printing a textile fabric by passing such textile fabric horison-tally between two flat relatively moving elec trodes closely spaced together to form an air gap and also having interposed between said electrodes and under. the fabric a thick glass plate which compr s applyin an alt rn t n curren electric field of about 30,000 to 45,000 volts to id electrodes a plyi a n d y floc y causing it to fall vertically through said field onto said fabric and interrupting the alternating current for one second out of ever-y four seconds, said actual volta e bein cont olle oss. the free air ga reventing tracing by passin a woolen belt through the space betvzeen the electrodes, said electrodes being horizontally positioned one above the .other so that there will be an upper electrode and a lowerelectrode and said upper electrode being fcram nous so as .to permit flock to fall vertically therethrough onto the fabric being treated, and the Step of causing the flock to fall velticallv upon and through the upper electrode to the fabric being treated between the electrodes.

References can m ne are of thi pa e UNITED STATES PATENTS 

